1. Field of the Invention
The present invention generally relates to an image forming apparatus, such as a facsimile machine, a copier, a printer, a multifunction machine including at least two of those functions, etc., and a developer supply method therefor.
2. Discussion of the Background
In general, an electrophotographic image forming apparatus, such as a copier, a printer, a facsimile machine, a multifunction machine including at least two of those functions, etc., includes an image forming mechanism for forming an electrostatic latent image on an image carrier, developing the latent image with developer, and transferring the developed image (toner image) onto a recording medium. As the developer, two-component developer in which toner and magnetic carrier are mixed is widely used.
The electronographic image forming apparatus has a developing unit, which typically includes a developing roller serving as a developer carrier that supplies the image carrier with the developer. The developing roller is partly exposed from an opening in the developing unit, and therefore, in such an image forming apparatus, the developer might spill out from the opening in the developing unit, particularly if a developer container part of the developing unit is filled with the developer before shipment and the developer container is shaken or the image forming apparatus tilts during transport. Further, the developer might deteriorate by being exposed to air. Therefore, the developer is typically put in the developer container part at a user's site.
In addition, because the magnetic carrier deteriorates over time and thus development capability is impaired with repeated use of the two-component developer, the developer including the degraded magnetic carrier should be periodically replaced.
As a typical developer replacement method, maintenance personnel visit the user each given cycle in order to collect the degraded developer and replenish the developing unit with unused developer. human error is inherent in such a method.
Herein, human error means the maintenance personnel might supply unused developer to the developer container part without removing the degraded developer therefrom, which is hereinafter referred to as redundant replenishment. Further, the maintenance personnel might forget having already filled it with the developer, and supply redundant developer to a developing unit of a newly installed image forming apparatus or a developing unit from which the degraded developer is removed.
As another example of human error, in a case of a color image forming apparatus including multiple developing units respectively corresponding to multiple color toners, the maintenance personnel might set a developer bottle of the wrong color to a developer supply port of the developing unit to which unused developer is to be supplied.
If redundant replenishment occurs, developer will spill over from the developing unit, and the developer remaining in the developer bottle will be spilled over the image forming apparatus when the developer bottle is removed from the developing unit, which might contaminate and damage the image forming apparatus.
Accordingly, there is a need to prevent such human error, as well as shorten a time period required to fill the developing unit with the developer and distribute the developer uniformly therein.